Centrifugal casting machine

ABSTRACT

The present disclosure relates to a casting machine, more particularly a centrifugal casting machine. The machine utilizes a casting head which clamps a mold in place. The mold is maintained in position by virtue of air pressure which acts upon the pressure plate of the casting head. The casting cycle may be automatically set as desired and the air pressure may also be set so as to maintain a constant and uniform value during the casting cycle.

United States Patent [1 1 Klobas Jan.9, 1973 [54] CENTRIFUGAL CASTING MACHINE [76] Inventor: Ivan Klobas, 70 Pitt Street, New York, N.Y. 10002 [22] Filed: Feb. 17, 1971 [21] Appl. No.: 115,997

[52] U.S. Cl ..164/292 [51] Int. Cl. ..B22d 13/10 [58] Field of Search ..l64/290, 286, 287, 288, 289,

[56] References Cited UNITED STATES PATENTS 2,415,620 2/1947 Woock ..l64/292 X 2,036,401 4/1936 Dailey 164/292 X 1,693,283 11/1928 Mix ..l64/290 1,908,607 5/1933 Hokin ..l64/29O Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. Brown A tt0rney-Joel Halpern [57] ABSTRACT The present disclosure relates to a casting machine, more particularly a centrifugal casting machine. The machine utilizes a casting head which clamps a mold in place. The mold is maintained in position by virtue of air pressure which acts upon the pressure plate of the casting head. The casting cycle may be automatically set as desired and the air pressure may also be set so as to maintain a constant and uniform value during the casting cycle.

9 Claims, 4 Drawing Figures PATENTEUJAH 9l973 3,709,287

' sum 1 or 3 IVAN KLOBAS I NVENTOR.

FIG.|

PATENTEUJAH 9192a 3.709.281

SHEEI 2 [IF 3 IVAN KLOBAS I NVENTOR.

PATENTED JAN 9 I975 3.709 287 SHEET 3 0F 3 IVAN KLOBAS INVENTOR.

CENTRIFUGAL CASTING MACHINE The present invention relates to casting machines and more particularly to centrifugal casting machines.

In its presently preferred form the invention relates to a centrifugal casting machine used in the production of articles of jewelry or components thereof.

Casting machines are well known as are centrifugal casting machines. In the jewelry art centrifugal casting machines have been used; however there is need for a centrifugal casting machine which exhibits reduced vibration during operation as well as for one which maintains substantially constant and uniform clamping pressure on the mold. U.S. Pat. No. 2,618,031 granted Nov. 18, 1952 to Samuel Mazer discloses a centrifugal casting machine for use in the jewelry field. The patentee employs a system of weights, levers and rollers actuated by the centrifugal force generated by the rotation of the casting head during operation of the machine. This system serves to urge a clamp plate into clamping position. However, it will be recognized that the force exerted by such clamp plate upon the mold id dependent upon and proportional to the rotational speed of the casting head. Variations in rotational speed leads to changes in centrifugal force and, therefore, to variations in the clamping pressure upon the mold. Such varying pressure during the molding cycle can result in the production of an inferior cast article and frequently lessens the useful life of the mold.

One object of the invention is the provision of a centrifugal casting machine which will maintain substantially constant and uniform clamping pressure on the mold during rotation of the casting head.

Another object of the invention is the provision of a centrifugal casting machine in which the clamping pressure is distributed substantially equally over the surface of the mold.

A further object of the invention is the provision of a centrifugal casting machine in which the mold can be readily clamped in place within the casting head'and in which ready access to the cast article is provided when the casting cycle has been completed.

Still another object of the invention is the provision of a centrifugal casting machine having automatic casting cycle controls.

Yet another object of the invention is the provision of a centrifugal casting machine which exhibits a minimum of vibration during rotation of the casting head.

Other objects and a more complete understanding of the invention may be obtained by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front elevational view of a centrifugal casting machine incorporating the invention;

FIG. 2 is a plan view of the centrifugal casting machine shown in FIG. 1;

FIG. 3 is a partial cross-sectional view of the centrifugal casting machine shown in FIG. 2 taken along line A-A; and

FIG. 4 is a perspective view of the locking bracket of the invention.

Referring to the drawings there is shown a centrifugal casting machine 1 mounted within a frame 2. The casting machine includes a top enclosure 3 carried by the frame which houses the casting head 4. The casting head comprises a cover plate 5 and a pressure plate 6,

the said plates being adapted to clamp the mold 7 therebetween.

Pressure plate 6 is carried by an end of slidable shaft 8 which, in turn, is journaled within guide member 9 rigidly connected to theinterior of cylinder 10 within which the shaft may reciprocate. The end of shaft 8 remote from the aforementioned end which supports the pressure plate has pressure distributor flange 11 affixed thereto. A sealing member 12 is positioned in contiguous relation to one face of said flange and is preferably held in place against the flange by washer 13 and nut 14. Other means may, of course, be provided for retaining the sealing member against the flange.

Cylinder 10' is closed at its lower end by air inlet member 15 having an axial opening to receive air line 16 for the introduction of pressurized air into the lower end of the cylinder. The air line is journaled in bearing 43 so that it remains stationary during the casting cycle. The walls of the cylinder, sealing member 12 and the upper surfaces of air inlet member 15 define air chamber 17 in the lower end of the cylinder.

The upper end of cylinder 10 terminates in an annular face plate 18 in which a central bore is provided to permit shaft 8 to slide therethrough.

Secured to the face plate of cylinder 10 at circumferentially spaced locations are a plurality of locking brackets 19. There are preferably four such locking brackets equally spaced circumferentially about the face plate. Arms 20, 21 are provided on each of the locking brackets to limit the upward movement of the cover plate 5. Means are provided on the cover plate, such as locking lugs 22, which are adapted to cooperate with a selected arm on each of the locking brackets to effectuate a locking of the cover plate to the locking brackets.

The top enclosure 3 comprises bottom wall 23, sidewall 24 and cover 25. The cover is desirably hinged at 26 to permit access to the casting head. Located on frame 2 is an air valve 27 adapted to be opened by contact with cover 25 or an element thereon upon movement of the cover to its opened position. The air valve is interposed in air line 16 which extends, as stated above, from the lower end of cylinder 10 to a compressor (not shown) or another source of pressurized air. Between the compressor and the air valve, as will be seen from FIG. l of the drawings, the air line passes into an air pressure regulator 28 which is adapted to maintain the pressure of the air in line 16 at a predetermined value. v

The top enclosure 3 is also provided with a micro switch 29 for automatic starting of the machine. Connected electrically to micro switch 29 is a cycle timer 30. This timer is of known mechanical and electrical construction. One such' timer is manufactured by Singer Industrial Timer Corporation of Parsippany, NJ. The cycle timer is preferably calibrated in minutes and fractional portions thereof. Once the desired setting has been made on the cycle timer, closing of the cover 25 actuates the micro switch and the cycle timer is thereby energized. The cycle timer is also electrically connected to motor M and the motor is energized simultaneously with energization of the cycle timer by the micro switch. When the casting cycle has been completed the cycletimer de-energizes the motor and the machine is stopped. Pilot lights may, if desired, be

incorporated to visually indicate termination of the casting cycle. Alternatively, audio signals may be provided.

Cylinder has mounted thereon a pulley 31 which is rotated by belt 32 connecting the pulley and motor M. Motor and pulley drives for centrifugal casting machines are well known and need not be discussed at length in the present specification. Spindle S may be provided in order to vary the tension on the belt 32 and thereby regulate the rotational speed of the pulley. The cylinder is rotatably journalled within top enclosure 3 by any known means such as ball or roller bearings 33 or by other known means.

Cover 25 is provided at the center thereof with an inlet 34 for the introduction of molding material to the mold. Aligned with the inlet and integral with cover plate 5 is a further inlet 35 which conducts the molding material to the interior of the mold.

The conventional mold employed in the production of cast articles of jewelry is formed of rubber or of synthetic plastic material and comprises an upper section designated the cope and a lower section designated the drag. Such a mold is placed between the cover plate 5 and pressure plate 6 of the present invention.

' As will be seen from FIGS. 2 and 3 of the drawings cover plate 5 is desirably formed with an integral upstanding flange to facilitate alignment of the inlet in the cover plate with the inlet in cover 25. Cover plate 5 is annular and is preferably given a number of locking lugs 22 equal to the number of locking brackets employed. The lugs are secured to cover plate 5 in any convenient manner such as by heavy duty rivets, bolts or the like. The lugs are secured to the plate so as to extend a sufficient distance beyond the periphery thereof to permit locking cooperation with one of arms or 21 on the locking bracket with which it is to be associated.

. Guide member 9 is dimensioned so as to have a bore sufficiently greater than the outside diameter of shaft 8 to'permit a bushing 36 to be interposed therebetween. The guide member is press fit against an internal shoulder 37 of the cylinder so as to be rigidly secured to said cylinder. The guide member is shaped with a radi ally extending portion which terminates at the inner and outer ends inreversely turned axially extending portions. If desired, the bushing 36 may be bonded to the radially inner axially extending portion.

Pressure distributor flange 11 is formed, preferably of aluminum, .in the shape of an annular disc with a central hub portion. The central bore of this flange is dimensioned such that the flange may be press fit onto shaft 8. Sealing member 12 comprises an annular disc and to the peripheral-portion of such disc is secured a flexible curved portion as will be seen from FIG. 3. The central portion may desirably be made of aluminum whereas the flexible curved portion may preferably be formed of rubber. The end of shaft 8 may be threaded to slidably receive washer 13 and to threadedly accept nut 14 to retain pressure distributor flange l1, sealing member 12 and washer 13 in close engagement.

As will be seen from FIGS. 3 and 4 of the drawings, locking brackets 19 are substantially L-shaped members having a base flange portion 38 extending to one side of upright web 39. Extending from each side of the web at substantially 90 from the base flange are arms 20 and 21. Ordinarily the lower arm is employed to effect locking of the cover plate 5. However, if the mold is of unusual thickness the cover plate may be locked by engagement of the locking lugs with the upper arm.

reference has been made to cylinder" l0 thishousing' may have other cross-sectional configurations although the cylinder is preferred.

It has been found that a 5i horsepower heavy duty ball bearing electric motor is suitable to provide the power to rotate the casting head at the desired rotational speeds. In cooperation with the variable pulley arrangement a wide range of rotational speeds may be obtained.

To operate the centrifugal casting machine of this invention the cover 25 is pivoted about its hinge to its open position. By opening the cover the micro switch moves to an off position insuring that cycle timer 30 and motor M are electrically disconnected. In so doing contact is also made with air valve 27 so as to reduce the pressure in the air line leading to cylinder 10. This reduction in pressure bleeds air from chamber 17 and results in a dropping of pressure distributor flange 11 and shaft 8. Since pressure plate 6 is supported by shaft 8, which bears against recess 42 in the bottom of the pressure plate, such plate also is caused to descend. Correspondingly, the mold and cover plate 5 drop thereby permitting the operator to unlock the cover plate from the locking brackets by a simple rotation of the cover plate. The cover plate is removed from the introduced into the mold. Cycle timer 30 is set for thedesired period of time for the casting cycle and the cover 25 is then closed. As soon as cover 25 is brought I out of engagement with air valve 27 pressurized air enters air line 16 and enters chamber 17 of cylinder 10. When sufficient air pressure builds up within chamber 17 sealing member 12 and pressure'distributor flange 1 l are forced upwardly carrying shaft 8 along. The top of the shaft urges pressure plate 6 upwardly and forces 'the mold tightly against cover plate 5 which, in turn, is

pressed up against the associated arm of the locking bracket so as to position the locking lugs in locked relationship therewith. Once cover 25 closes to the extent that the micro switch is engaged the cycle timer 30 and motor M are energized thus commencing a new casting cycle determined by the setting on the cycle timer.

From the foregoing description it will be seen that a centrifugal casting machine has been provided which is of special value in the casting of articles of jewelry. However, the machine may also be adapted for the production of cast picture frames and other articles.

While a cylindrical housing has been described it will be apparent that the configuration of such housing may, if desired, be modified according to the particular application of the machine. The machine is substantially vibration free, transmits a substantially constant and uniform pressure to the mold, transmits the pressure so as to be evenly distributed over the surface of said mold, and achieves the other objects stated above.

Although the invention has been described with a certain degree of particularity it will be understood that the machine disclosed is merely a preferred embodiment of the invention, that persons skilled in the casting art will recognize that numerous changes in the details of construction and in the arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What I claim is:

1. In a centrifugal casting machine having a frame, a rotatable casting head mounted on said frame, a pair of clamping plates for retaining a mold therebetween in said casting head, means for introducing molding material into said mold, means for locking said plates and mold as a unitary assembly during the casting cycle, means for rotating said casting head at predetermined rotational speeds, and fluid pressure means for moving one of said clamping plates into position for locking engagement with the other of said clamping plates, the improvement which comprises means for transmitting pneumatic pressure to said one of said clamping plates to force said plate, the mold, and the other of said plates into locking engagement with said locking means, pneumatic pressure-regulating means being provided for maintaining said predetermined pressure on said one plate at a substantially constant value regardless of rotational speed during the casting cycle, said plates being inseparable until reduction of said pneumatic pressure below a predetermined value.

2. In a centrifugal casting machine having a frame, a top enclosure mounted on said frame, a casting head rotatably mounted within said top enclosure, said casting head including first and second clamping plates for retaining a mold therebetween, said first plate having an opening therein for the introduction of molding material to said mold, the improvement which comprises a housing rotatably mounted adjacent one end thereof in said top enclosure beneath said second clamping plate, said one end of said housing being closed by a face plate, a shaft mounted within said housing so as to be slidable therein, said face plate having a central bore to permit said shaft to slide therethrough and into contact with the lower side of said second clamping plate, the other end of said housing being closed except for pneumatic fluid inlet means adapted to conduct pressurized gas into said housing, said other end of said housing being rotatably connected to said pneumatic fluid inlet means, means for introducing pressurized gas through said inlet means and into a chamber located in the lower end of said housing, flange means being affixed to said shaft and defining the upper wall of said chamber and sealing said chamber from the portion of the housing thereabove, locking means secured to said face plate of said housing for limiting the movement of said first clamping plate in one direction and for cooperating therewith to prevent rotation of said first plate relative to said locking means during the casting cycle, means for regulating the introduction of said pressurized gas into said chamber at the start of a casting cycle, for maintaining the pressure of said gas at a substantially constant value during the casting cycle and for reduc ing the pressure within said chamber after the casting cycle has been terminated, and means for rotating said housing and the casting head locked thereto at predetermined rotational speeds.

3. A centrifugal casting machine according to claim 2, wherein said housing is generally cylindrical in crosssection, the said face plate thereof being annular and having an outer surface substantially coextensive with the overlying surface of said second clamping plate.

4. A centrifugal casting machine according to claim 2, wherein said locking means comprises a plurality of locking brackets, each of said locking brackets being substantially L-shaped and having an upright web, a base flange extending to one side of said web, and at least two arms extending from said web at substantially from said base flange, each of said arms terminating in a depending flange.

5. A centrifugal casting machine according to claim 4, wherein-said first plate comprises a cover plate having an integral upstanding flange with an axial opening extending therethrough adapted to conduct molding material to said mold, said cover plate being provided with a plurality'of spaced locking lugs secured thereto and extending beyond the periphery of said cover plate, the spacing of said locking lugs being such as to permit same to cooperate with a selected arm on each of said locking brackets and with the depending flange thereon to lock said cover plate in place under the influence of said pneumatic pressure during the castin cycle.

6. A centrifugal casting machine according to claim 2, wherein a guide member is positioned within said housing in rigid engagement with a shoulder of the inpressurized gasinto said chamber and for maintaining.

the pressure of said gas at a predetermined value comprises a pressure regulator-interposed in the gas line communicating a source of pressurized gas and the inlet means of said housing, and said means for reducing thepressure within said chamber comprises a valve interposed in said gas line between said pressure regulator and said gas inlet means.

8. A centrifugal casting machine according to claim 2, wherein a micro switch is provided in said top enclosure adapted to be activated upon closure of said cover, said micro switch being adapted, upon activation by said cover, to energize a cycle timer connected to said means for rotating the housing and casting head whereby said housing and casting head are rotated for the predetermined casting cycle. g

9. A centrifugal casting machine according to claim 7, wherein a micro switch is provided in said top enclosure adapted to be activated upon closure of said cover, said micro switch being adapted, upon activation by said cover, to energize a cycle timer connected to said means for rotating the housing and casting head whereby said housing and casting head are rotated for the predetermined casting cycle. 

1. In a centrifugal casting machine having a frame, a rotatable casting head mounted on said frame, a pair of clamping plates for retaining a mold therebetween in said casting head, means for introducing molding material into said mold, means for locking said plates and mold as a unitary assembly during the casting cycle, means for rotating said casting head at predetermined rotational speeds, and fluid pressure means for moving one of said clamping plates into position for locking engagement with the other of said clamping plates, the improvement which comprises means for transmitting pneumatic pressure to said one of said clamping plates to force said plate, the molD, and the other of said plates into locking engagement with said locking means, pneumatic pressure-regulating means being provided for maintaining said predetermined pressure on said one plate at a substantially constant value regardless of rotational speed during the casting cycle, said plates being inseparable until reduction of said pneumatic pressure below a predetermined value.
 2. In a centrifugal casting machine having a frame, a top enclosure mounted on said frame, a casting head rotatably mounted within said top enclosure, said casting head including first and second clamping plates for retaining a mold therebetween, said first plate having an opening therein for the introduction of molding material to said mold, the improvement which comprises a housing rotatably mounted adjacent one end thereof in said top enclosure beneath said second clamping plate, said one end of said housing being closed by a face plate, a shaft mounted within said housing so as to be slidable therein, said face plate having a central bore to permit said shaft to slide therethrough and into contact with the lower side of said second clamping plate, the other end of said housing being closed except for pneumatic fluid inlet means adapted to conduct pressurized gas into said housing, said other end of said housing being rotatably connected to said pneumatic fluid inlet means, means for introducing pressurized gas through said inlet means and into a chamber located in the lower end of said housing, flange means being affixed to said shaft and defining the upper wall of said chamber and sealing said chamber from the portion of the housing thereabove, locking means secured to said face plate of said housing for limiting the movement of said first clamping plate in one direction and for cooperating therewith to prevent rotation of said first plate relative to said locking means during the casting cycle, means for regulating the introduction of said pressurized gas into said chamber at the start of a casting cycle, for maintaining the pressure of said gas at a substantially constant value during the casting cycle and for reducing the pressure within said chamber after the casting cycle has been terminated, and means for rotating said housing and the casting head locked thereto at predetermined rotational speeds.
 3. A centrifugal casting machine according to claim 2, wherein said housing is generally cylindrical in cross-section, the said face plate thereof being annular and having an outer surface substantially coextensive with the overlying surface of said second clamping plate.
 4. A centrifugal casting machine according to claim 2, wherein said locking means comprises a plurality of locking brackets, each of said locking brackets being substantially L-shaped and having an upright web, a base flange extending to one side of said web, and at least two arms extending from said web at substantially 90* from said base flange, each of said arms terminating in a depending flange.
 5. A centrifugal casting machine according to claim 4, wherein said first plate comprises a cover plate having an integral upstanding flange with an axial opening extending therethrough adapted to conduct molding material to said mold, said cover plate being provided with a plurality of spaced locking lugs secured thereto and extending beyond the periphery of said cover plate, the spacing of said locking lugs being such as to permit same to cooperate with a selected arm on each of said locking brackets and with the depending flange thereon to lock said cover plate in place under the influence of said pneumatic pressure during the castin cycle.
 6. A centrifugal casting machine according to claim 2, wherein a guide member is positioned within said housing in rigid engagement with a shoulder of the interior wall thereof, a bushing being disposed within the central opening of said guide member and having a bore of sufficient diameter to slidably accomodate said shaft.
 7. A centrifugal casting machine accordinG to claim 2, wherein said means for regulating the introduction of pressurized gas into said chamber and for maintaining the pressure of said gas at a predetermined value comprises a pressure regulator interposed in the gas line communicating a source of pressurized gas and the inlet means of said housing, and said means for reducing the pressure within said chamber comprises a valve interposed in said gas line between said pressure regulator and said gas inlet means.
 8. A centrifugal casting machine according to claim 2, wherein a micro switch is provided in said top enclosure adapted to be activated upon closure of said cover, said micro switch being adapted, upon activation by said cover, to energize a cycle timer connected to said means for rotating the housing and casting head whereby said housing and casting head are rotated for the predetermined casting cycle.
 9. A centrifugal casting machine according to claim 7, wherein a micro switch is provided in said top enclosure adapted to be activated upon closure of said cover, said micro switch being adapted, upon activation by said cover, to energize a cycle timer connected to said means for rotating the housing and casting head whereby said housing and casting head are rotated for the predetermined casting cycle. 